For decades, urea formaldehyde (UF), phenol formaldehyde (PF), and melamine formaldehyde (MF) binder compositions have been used to make glass fiber mats for building materials, including insulation, flooring, siding, facers, and roofing shingles. UF binders were favored for these materials because of their low cost and acceptable strength properties. For materials like roofing shingles, the UF in the binder compositions were often blended with more flexible latex polymers such as polyvinyl acetate, vinyl acrylic, and/or styrene butadiene polymers. The latexes in the binders gave the shingles increased tensile and tear strength, as well as improved their moisture resistance properties.
More recently, the construction industry has moved away from formaldehyde-based binder compositions. Formaldehyde is considered a probable human carcinogen, as well as an irritant and an allergen, and its use in binder formulations for building products, textiles, upholstery, and other materials is increasingly restricted. Thus, makers of building materials have been developing alternative binder formulations that are formaldehyde free.
One alternative binder system that has received considerable attention includes the polymerization of carbohydrates (i.e., sugars) with amine compounds to make a binder that is insoluble in water and adheres well to glass fibers. In addition to being formaldehyde-free, these carbohydrate-based binder formulations can be made from renewably grown natural sugars instead of non-renewable, petroleum-based feedstocks.
Compounds used in the processing of formaldehyde-free binder systems and in making formaldehyde-free fiber composites may ultimately weaken the composite or materials near the composite. Thus, there is a need for alternative compositions and methods to produce formaldehyde-free fiber composites.